Variation in skin temperature resulting from a temporary vasostimulant such as a temporary occlusion of an artery in a limb has been studied. It is established that, properly conducted in the context of other variables, this study can provide valuable evidence of a subject's cardiovascular health by providing a quantitative measure of the subject's vascular function. The previously established method of assessing vascular function based on monitoring of fingertip (digital) skin temperature before, during, and after applying a temporary vasostimulant has been termed Digital Thermal Monitoring, or DTM. The inventors have automated the DTM test procedure, and this automation has eliminated the inter-operator variability that is commonly observed when DTM tests, and any other cuff reactive hyperemia tests, are performed manually by different operators. However, it was recognized that variability of test results due to environmental conditions and subject preparation can still exist. What is needed are additional ways of improving the reproducibility and technical quality of DTM tests, as well as ways of identifying the presence of specific subject and testing conditions that may influence the DTM test results.